When I click on a city the option to attack the city is not always available as an option. I am getting attacked by a particular city and hen I tried to attack back the only available options for me was the information and the trade buttons. Please fix the problem.

When I click on on some cities I do not get all the options particularly the attack button. Example: a city is attacking my city but when I click to attack them I get only the information and trade buttons and not the attack option button. Thanks